What is the reason for your interest in this problem? Why this particular form for D? I don't see how the choice of indices i=1 and n for the 1/2 elements can be relevant. Why not i=1 and 2? Why exactly two such indices? Why the values 1/2 and 1/3? What have you done to try to attack the problem?
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Ben CrowellJan 27 '13 at 18:37